Do these mount using factory bed holes, or will I need to drill?

They mount at factory attachment points — no drilling. You'll bolt straight into the existing connection holes on your bed frame.

What hardware do I need to install these?

Fasteners are not included with these rails. You'll need bolts and washers sized to match your truck's factory bed mounting holes — check your vehicle's service manual or bed frame attachment points for the correct spec.

Can I paint these, or do they need prep work?

The black finish ships ready to install as-is. If you want to paint them, light scuffing with 220-grit sandpaper and a clean wipe-down will prepare the surface for primer and top coat.